A driving assistance apparatus mounted on a vehicle (such as an automobile) is proposed as a system that determines and notifies prediction of collision between a subject vehicle and a different vehicle at an intersection based on positions, travel directions, speeds, and map information about the subject vehicle and the different vehicle (such as a two-wheel vehicle or a four-wheel vehicle) (e.g., see patent literature 1).
A related technology is described below. The related technology does not necessarily constitute prior-art.
FIG. 5(a) illustrates an example of specifying intersection C where subject vehicle A is predicted to pass, based on vehicle information such as the position or the travel direction of subject vehicle A and based on road map information. This settles: determination target areas T1 and T2 where different vehicles B1 and B2 having possibilities of collision are present; and reference points P1 and P2 where the collision may occur.
Suppose that different vehicles B1 and B2 travel toward reference points P1 and P2 in determination target areas T1 and T2 acquired by the communication. In this case, the collision prediction is determined by calculating the time at which subject vehicle A, and different vehicles B1 and B2 reach reference points P1 and P2. The collision, if predicted to be likely to occur, is audiovisually notified to a driver. Collision estimation information is also transmitted to different vehicles B1 and B2. This invites attention of drivers of subject vehicle A, and different vehicles B1 and B2.
However, the above-mentioned related technology determines the collision prediction based on whether vehicles A, B1, and B2 are traveling toward predetermined reference points P1 and P2. In FIG. 5(b), for example, road R2 is shaped to merge from sideways to main road R1 where subject vehicle A is traveling so that road R2 connects to road R1 at an obtuse angle or along a curve. In this case, immediately before different vehicle B enters intersection C (area T1), it is determined that vehicle B is traveling toward reference point P1.
A drive support system according to the related technology can determine a probability of collision with a different vehicle by using the road map data, but cannot ensure sufficient accuracy concerning reliability of the collision prediction. The drive support system according to the related technology does not consider a road width or a limiting speed in a vehicle speed when calculating a collision timing, and cannot finely determine the collision prediction.